With the shrinkage of the IC device dimensions, Cu and ultra-low-k dielectric were introduced into IC devices to reduce RC delay. Ultra-low-k dielectrics generally suffer more damage than silicon oxide dielectric during process integration and subsequently cause reliability degradation. Therefore, ultra-low-k damage characterization on Cu damascene structures is of great importance to understand the damage mechanisms. This paper describes the application of UV-Raman microscopy with enhanced spatial resolution and signal sensitivity for characterizing ultra-low-k dielectric in the three-dimension structure of Cu metallization with nanometer feature size. It shows UV-Raman technique has an advantage in analyzing ultra-low-k layer on patterned wafer and extracting ultra-low-k signals from Cu/ultra-low-k mixed structure. UV-Raman is also effective to characterize the ultra-low-k degradation for ultra-low-k related reliability analysis by time dependent dielectric breakdown (TDDB) test.